I think the misfiring maybe from low cold cranking amps i.e. the battery maybe on the way out, thats if it's not misfiring after say 10mins of driving. Or because of the fuel issue.
The white smoke could be caused from a number things all fuel related, low compression from worn valve stem seals, glazed pistons/bore, worn rings etc. or faulty fuel injectors, junked up, old etc. or incorrect fuel injection timing/duty cycle - if your tune is already rich(safe tune) start up is going to be ultra rich. Try the easy solution first, adjust the screw on the iac valve, this lets the motor run a bit leaner on startup.